Kaguya (mouse)

Kaguya was a laboratory mouse created in Japan in 2004 by a team led by Tomohiro Kono at the Tokyo University of Agriculture. She was the first mammal to be created using the genetic material from two female mice, a process called biparental reproduction. This achievement challenged the long-held scientific understanding that mammalian reproduction required both male and female genetic contributions.

The creation of Kaguya involved manipulating the genes of unfertilized egg cells from one mouse and injecting them into the egg cell of another mouse whose genes were modified to enhance growth potential. Specifically, one egg cell was modified to suppress the expression of imprinted genes that are normally active only in males, while the other egg cell donated its nucleus to the first.

Kaguya lived a normal lifespan and was able to give birth to offspring herself, demonstrating the viability of this artificial reproductive method. Her creation provided valuable insights into genomic imprinting, a process where certain genes are expressed differently depending on whether they are inherited from the mother or father. The research contributed to a better understanding of mammalian development and potentially opened up avenues for exploring new reproductive technologies, although the ethical implications of such technologies continue to be debated. Further research using this technique has been limited by its low success rate.